View Full Version : Welding Aluminum?

07-16-2007, 12:50 PM
I've done enough stick welding of steel to know how to at least keep both parts together! :) But now, I'm thinking of aluminum.

I believe a MIG is the proper way to go, or would it be TIG?

My project would be some aluminum handrails, probably square stock with square pickets. At least I would want the welds to be "presentable", since it is a handrail. Also, it can be switched over to weld steel too, right?

So how expensive is one of these rigs, and how difficult is it to learn? Mind you, I would not be doing this full time, and only an occassional job, so I don't want to buy the "top shelf" rig.

07-16-2007, 01:09 PM
A mig will work good, there are small wire feeds like a Lincoln that will run aluminum, fluxcore and stainless. they start around $600

If you want to do a good job a tig is better, they start about $1,500+ but a tig will weld most anything.

Tig is not bad to learn, just like any type of welding lots of practice is everything.

07-16-2007, 02:18 PM
I build a few custom aluminum racks, trailers, etc..., as a side job/hobby.
My observations are that a spool gun works well about 3/16" and over, especially when you can get your work flat or downhill. I have had mixed results at 1/8", laps and tee's are easier than butts on thinner material with this process.
I prefer TIG any time it is visible, thin, or overhead. It is slower but after a few years you get pretty fast. You have to learn to adjust a few more parameters but the results can be awesome. The above picture is not my best work just an example of the scalloped weld typical of TIG.

Pulsed mig is another option I have been looking into how to utilize this process without buying an expensive push-pull gun setup. I have ran aluminum wire through my regular mig gun with the hose really straight but it can be problematic because the wire is so soft.

A spool gun and a MIG welder is cheaper and more versatile as a first setup. I would steer my friends this way to start out.

There are probably a few guys here that are so good they will laugh at the pics I posted, please be kind.

07-16-2007, 05:36 PM
If you're going TIG just remember you need an AC machine. Many people have bought cheaper DC TIG welders only to find you can't weld aluminum (aluminium over here!) with them.

Brisbane Australia.

Your Old Dog
07-16-2007, 06:08 PM
If you plan on MIG welding aluminum thick enough for a hand rail to look nice make sure you get a big enough unit. The smaller $600 120Volt units will require you preheat the aluminum. I understand the spool guns cost as much or more than the welder. I went MIG, I wish I had gone with TIG instead.

07-16-2007, 11:20 PM
To Mig aluminum you really need a substantial machine and a wire gun unless you like to clean up birds nests of aluminum wire. If you already have a burly mig, get a feeder and a bottle of argon and have at it, but I'd very much recommend that a Tig welder is a wonderful thing to have.

I got a Miller Synchrowave 180 in like-new used condition with a big bottle and a ton of consumables for about $1800. Shortly thereafter I was gifted a torch cooler so I got an LC torch. There's jobs that nothing else will do anywhere near as well.

Then I lucked into a MillerMatic 185 Mig a while later when on a Craigslist compressor buying expidition. Now I've got 2 hulking blue units in the garage waiting to do damage to my electric bill.

Go Tig, or go home...

loose nut
07-17-2007, 09:06 PM
If you're going TIG just remember you need an AC machine. .

you need an AC machine with a high frequency unit (or built in). The high frequency helps break up the oxidation that starts to form as soon as you clean the aluminum. Also the metal needs to be squeaky clean.

07-18-2007, 10:22 AM
"The high frequency helps break up the oxidation that starts to form"

Not true, the HF is just there to intiate arc.
I've used a few old AC machines with scratch start on ali.
As long as you have AC, preferably adjustable, you'll do fine.
The - half cycle does the heat, the + half cycle cleans off the oxide film. It's an amazing thing to watch!

07-18-2007, 10:33 AM
I also have a Miller Synchrowave 180 and would highly recommend this machine for welding aluminum handrails. While the cost for this setup is $1500 to $1800 I think by the time you check into the Mig option you will find the cost much higher due to the need for a spool gun to avoid bird's nests. The appearance of the Tig weld is far superior especially when working with thin materials. Just my 2 cents worth.

loose nut
07-18-2007, 09:42 PM
"The high frequency helps break up the oxidation that starts to form"

Not true, the HF is just there to intiate arc.
I've used a few old AC machines with scratch start on ali.
As long as you have AC, preferably adjustable, you'll do fine.
The - half cycle does the heat, the + half cycle cleans off the oxide film. It's an amazing thing to watch!

Hate to argue but it does help break up the oxides, I set the tig machine at work to about 10% on straight polarity for steel etc. to initiate an arc but crank it up to 100% for aluminum and there is a noticeable improvement, also the manuals that we had in our training years ago also quoted this effect. The AC does produce most of the cleaning but some of the better tig machines have a lot of different settings that can change how welding aluminum works IE. maxi mun clean ,maximum penetration etc. You have to check the manuals for each different machine to see the effect this makes .

07-19-2007, 01:26 PM
At the risk of going off-topic here I have to back up what Swarf and Sparks said about cycles doing the work... There may be reasoning to HF cleaning effects but I have never seen the effect on the width cleaning border.

For those that don't already know the setting that Loose Nut refers to (maximum cleaning vs. maximum penetration), is changing the EP and EN time percentages. EP is electrode positve, the arc is travelling to the tungsten, oxide is lifted. EN is electrode negative, electrons are flowing to the work, the majority of the heating is done during this stage. On a transformer based machine such as a syncrowave the range of adjustment is less than an inverter based TIG unit like a Dynasty. The HF adjustment is an intensity setting. It helps to establish and maintain the arc. I use just enough HF to get consistent starts when I push the pedal I have never seen a benefit to using more - maybe I don't know what to look for.

Try using just enough EP or "cleaning" so that you get only an 1/8" border or so on your weld bead. You will notice you have less preheat time needed, thus less heat into the bulk of the material and a more focused weld area. The nice thing about using less EP is your tungsten will stay sharp and I think the arc is easier to direct with a sharp tungsten.

07-19-2007, 03:18 PM
Hold up - what type of stick welder do you have? If you have DC reverse polarity as an option, your good to go. Buy some aluminum welding rods from Lincoln electric or etc. They sell several different varieties for different applications. They weld about the same as "normal" welding rod but you can really see a molten puddle... since the aluminum doesnt really glow.

I've welded all the way down to under 1/16" thick square tubing with a stick welder. I even submitted some test coupons to destructive tests with checks for cracks along the way with a cylinder head test kit. (the deal with the dust and light) Very nice results. I've tried welding aluminum with a mig unit and spool gun and found that welding it with a stick welder on reverse polarity was much easier to pick up and left me with very nice looking welds. of course, i prefer stick to mig normally anyway - i always end up with better looking welds with a stick than a mig... anyhow, just something to consider.

You might as well buy a package for 8 bucks or whatever and see how you get along, if you dont like it then you can consider buying a new welder and your only out a few bucks. If you like it you just saved several hundred at least!

Michael Moore
07-19-2007, 04:06 PM
I just took delivery of a new Syncrowave 250 but I've only done some thick steel pipe so far. I'm looking forward to seeing how the square wave does on aluminum compared to the old Miller Gold Star 330 I had before. There's a PDF brochure on the 250 on the millerwelds.com site (http://www.millerwelds.com/pdf/spec_sheets/AD4-2.pdf) that has an illustration of how changing the AC balance affects the cleaning and penetration on an aluminum weld.

Keep in mind that aluminum needs a LOT more heat put into it than steel does. Be sure to look at the duty cycle on whatever machine you get. The 250 has a 40% cycle at 250A, 60% at about 200A, and 100% at 150A.

Thinner aluminum can be torch welded. I made the water tank for my old Miller TIG from .125" 6061 plate and gas welded it together.


07-20-2007, 12:37 PM
Here's one from outside the box, literally. A Ready-Welder DC battery or stick box powered MIG spool gun. $400 from a certified dealer on ebay. http://www.readywelder.com/

I've had a Ready-Welder for 8 years, and have used it on plenty of aluminum, in addition to carbon & SS steel. One job was 1/4 rod to 7/8 dia, .065 wall tube, It took me some practice not to burn through, but I got the hang of it. It's a cheap, versatile tool. They claim the military is fond of it. You can't touch another spool gun or tig at anywhere near this price.